Method for preparing prepressed cheese curd blocks and an assembly for carrying out said method

ABSTRACT

A method for the preparation of prepressed cheese curd blocks (38), where a curd (2) comprising a mixture of curd grains (42) and whey is fed to a conveyor belt (19) and the curd grains (42) are collected and shaped during continuous movement of the belt by being subjected to prepressing means (27) and side-limiting walls (18). The resulting cheese body (30) is cut into suitably dimensioned blocks at a cutting station (37). The curd (2) is fed to the continuously moving conveyor belt (19) below the surface (40) of a whey pool (39) and during the movement of the conveyor belt (19) said curd is conveyed along an oblique path above the surface (40) of the whey pool (39) simultaneous with it being subjected to prepressing means (27). The whey pool is contained in an obliquely installed vat (7), the conveyor belt (19) being introduced at the bottom end of said vat and leaving it at its top end ( 20). Said top end (20) has no end wall, thus providing space for the cut blocks (38) to pass out of the vat (7) just before the top end (20).

TECHNICAL FIELD

The present invention relates to a method for preparing prepressedcheese curd blocks, where a curd comprising a mixture of curd grains andwhey is fed to a conveyor belt and the curd grains are collected andshaped during continuous movement of the belt by being subjected toprepressing means and side-limiting walls, whereupon the resultingcheese body is cut into suitably dimensioned blocks at a cuttingstation.

BACKGROUND ART

During the preparation of cheese types, such as Edam, Jarlsberg andDanbo (all registered trademarks), the prepressing part of the processis decisive for the characteristic texture of the cheese. The abovecheese types are compact having uniform, circular fermentation holescaused by carbon dioxide formed during the ripening. Originally theprepressing was performed at the bottom of the cheese vat, in which thecurd had been prepared. Subsequent to the final stirring the cheesegrains were dragged up to one end of the cheese vat by means of aperforated plate or wall. Thus the cheese grains were separated from themain part of the free-flowing whey. The small, preferably rectangulararea holding the cheese grains was then covered by a heavy press screen.At the same time the draining of the whey was started from the oppositeend of the vat. The pressure on the resulting cheese block was graduallyincreased by means of weights evenly distributed on the press screen.After 10-30 min the press screen was removed and the drained cheeseblock was cut into suitable pieces, which were then conveyed to the nextpart of the process: forming and final pressing.

This known method is only suitable for the cheese making from smallportions of cheese milk (up to approx. 6,000 1). Otherwise the area ofthe cheese blocks is so large that the free-flowing whey cannot escapeduring prepressing. This results in texture defects in form of smallirregular holes under the rind in the finished cheeses due to thepresence of whey with a high concentration of lactose causingfermentation along the rim of the cheese block.

When large cheese vats and closed cheese tanks were introducedprepressing in the vat became impossible and special prepressing vatswith perforated plates above the bottom and fixed walls were introducedinstead. Subsequent to the final stirring in the cheese vat or tank thewhey-and-cheese grain mixture was pumped or dumped into a prepressingvat. During this step air is automatically entrapped in the whey, saidair being difficult to remove before the beginning of the prepressing.The air is likely to cause fat oxidation and defects in the cheese.Moreover, air bubbles are retained under or in the perforated bottomplate, said bubbles gradually meandering into the cheese duringprepressing.

Since then continuously operating assemblies have been developed, wherethe cheese is prepressed in columns by means of the weight of itsgrains; the free-flowing whey is continuously drained off in perforatedzones. The problem of entrapped air does, however, still exist, as thecomparatively high columns of whey and cheese grain do not offersufficient escape possibilities.

The Danish patent application 5022/85 discloses a method for thepreparation of curd blocks for the preparation of cheeses by removingthe whey from the curd. In this method the curd is fed to a drainingbelt, whereon the resulting curd body is subjected to stepwise forwardmovement while the whey is removed. The curd is fed to the draining beltvia an antechamber the bottom of which is formed by the draining belt.This antechamber is separated from the following part by means of apartition forming a small gap opposite the draining belt. As a resultthe curd is fed to the draining belt under overpressure initiating theseparation of the whey. After having passed the partition the curd orcheese body formed by the cheese grains expands. While still beingconveyed by the draining belt the curd body is subjected to prepressingmeans giving it the desired thickness. Simultaneously the desired widthis determined by adjustable side walls. Then the cheese body is cut intoblocks of predetermined size.

DISCLOSURE OF THE INVENTION

The inventive method is characterised in that the curd is fed to thecontinuously moving conveyor belt below the surface of a whey pool andduring the movement of the conveyor belt said curd is conveyed along anoblique path above the surface of the whey pool simultaneous with itbeing subjected to prepressing means.

This results in a continuously operating prepressing method, whereby aproduct is obtained at a comparatively large capacity, said producthaving the desired texture without defects. This is especially due tothe fact that the cheese grains are allowed to collect without beingdisturbed while they are in the whey, thus enhancing the fusing process.Furthermore, the whey is gradually pressed out by means of prepressingmeans in accordance with originally used prepressing methods in a cheesevat. Without the desired fusing process the resulting cheese easilyobtains a Havarti-like texture, where the grains are still visible.

The curd is preferably fed to the conveyor belt at such a slow velocitythat the cheese grains are deposited below the surface of the whey poolwith no further influence than the force of gravity and the movement ofthe whey.

The invention relates furthermore to an assembly for carrying out themethod as claimed in claim 1, said assembly including a pump, wherefromthe curd is fed to an endless conveyor belt via an inlet pipe, saidconveyor belt running along a support plate and extending from thedelivery mouth of the inlet pipe to a cutting station for cutting offcheese blocks of a predetermined size from a cheese body resulting fromthe shaping of the collected cheese grains along the side-limitingwalls, while the curd is subjected to prepressing means. This assemblyis characterised in that the support plate and the side-limiting wallsare formed by an oblong, oblique vat without top end walls, the bottomend wall of said vat being provided with means for introducing theconveyor belt, and the conveyor belt is a continuously moving belt, andthe vat has means to maintain the desired level of the whey pool, andthe delivery mouth of the inlet pipe is below the adjusted level of thewhey pool.

This is an especially suitable assembly allowing the undisturbeddeposition of the cheese grains without entrapping air.

In a preferred embodiment the conveyor belt is provided with evenlydistributed holes, and the bottom of the vat has identations at leastwithin an area below the delivery mouth of the inlet pipe, saidindentations being connected with one or more outlet openings for theliquid, said outlet openings being adjacent the bottom end wall. As aresult, the whey in the whey pool flows down towards the bottom of thevat and the bottom end wall, so that the cheese grains are also draggeddown towards the conveyor belt, where they collect and form a cheesebody.

According to the invention the area of influence of the prepressingmeans extends from a level below the surface level of the whey pool to alevel above said surface level. As a result the pressing of the whey isinitiated while there still is a large amount of whey thus enhancing thepressing and ensuring that a sufficient amount of whey is pressed out ofthe cheese body before the cutting of the cheese into blocks.

Furthermore, according to the invention, there is a scraper plate foradjusting the desired thickness of the cheese body formed by the cheesegrains directly in front of the prepressing means, seen in the directionof transport, resulting in a comparatively easy adjustment of thedesired thickness of the cheese body.

The inventive inlet pipe, seen in the flow direction of the curd,extends upwardly and over the top edge of the bottom end wall of the vatand from there obliquely down into the vat in a direction away from thebottom end wall of the vat, and said pipe is of substantiallyrectangular cross-section the length of said cross-section, seen in thetransverse direction of the vat, increasing in a direction towards thedelivery mouth until said pipe has approximately the same width as thevat. This results in an especially undisturbed feeding of the curd tothe whey pool in the vat. Simultaneously, it is ensured that the cheesegrains are automatically distributed across the entire width of theconveyor belt.

Moreover, the delivery mouth of the inventive inlet pipe comprises asubstantially planar chute extending downwards into the whey in the vat,said chute being provided with perforations or openings. As a result,the whey is removed through the holes while passing down the chute andflows down towards the bottom end of the vat so that the whey does notunnecessarily whirl up the cheese grains. This enables the cheese grainsto collect falling like snow flakes into the whey pool forming a slopewith comparatively uniform inclination down towards the conveyor belt inthe direction towards the bottom end of the vat. The comparativelyuniform inclination and the open chute allow a relatively easysupervision of the correct operation of the assembly and the adjustmentof the yield of the pump.

In a further embodiment of the invention there are, in front of thescraper plate, horizontally displaceable rake-like means levelling thesurface of the cheese body before it passes beneath the scraper plate,the outer teeth of said rake-like means being flexibly journaled, seenin the direction of displacement. Thus the cheese grains are evenlydistributed across the entire width of the conveyor belt before theypass beneath the scraper plate, further ensuring that a uniform productis prepared. The outer teeth of the rake-like means are resilient inorder to prevent cheese grains from being pressed up along the sides ofthe vat at a level above the surface of the cheese body during thereciprocating movement of the rake-like means across the conveyor belt.

In yet a further embodiment of the invention there is a suction meanssucking out whey following the scraper plate, seen in the direction ofmovement of the cheese body, ensuring a desired control of the whey flowin a forward direction passing the scraper plate at the place inquestion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail below and with reference tothe accompanying drawings, in which

FIG. 1 is a diagrammatic side view of an assembly for carrying out theinventive method, and

FIG. 2 illustrates on a larger scale a perpendicular, longitudinallysectional view through a part of an inlet pipe suitable for feeding curdto a vat of the inventive assembly.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates an assembly for the preparation of prepressed curdblocks or cheese blocks comprising a storage container 1 provided forthe temporary storage of a curd 2 to be supplied via an inlet 3 from aknow cheese vat (not shown). Inside the storage container 1 there is astirrer 4 driven by a motor 5. The stirrer ensures that the cheesegrains remain comparatively evenly distributed in the whey until thecurd 2 is fed into a vat 7 via a pump 6. The pump 6 is connected with aninlet pipe 9, shown on a larger scale in FIG. 2, via a pipe 8. The inletpipe 9 extends upwardly and over a top edge 10 of a bottom end wall 11of the vat 7, cf. FIG. 1. From the delivery mouth of the inlet pipe 9 tothe area over the top edge 10 of the bottom end wall 11 of the vat 7 thecross-section of the inlet pipe 9 increases from a circularcross-section corresponding to the cross-section of the pipe 8 to anoblong, substantially rectangular cross-section, the length of saidcross-section in the transverse direction, seen perpendicular in thedrawing, increasing gradually until it has a width corresponding to thewidth of the vat 7.

As is apparent from FIG. 2, the outlet of the inlet pipe 9 has the formof a chute 12. The chute 12 has a planar bottom 13 and side walls 14,one of which is shown in FIG. 2. The chute 12 can be a separate partfastened to the inlet pipe in a manner not shown. Optionally the chutecan comprise several, telescopic parts so that the length of the chuteis adjustable. A section close to the outlet end 15 of the chute isprovided with perforations 16 allowing the passage of whey but not ofthe cheese grains of the curd.

The vat 7 is oblong, obliquely arranged, and has, as mentioned before, abottom end wall 11 but no top end wall. It is furthermore equipped witha bottom 17 and side walls 18 extending along the longitudinal directionof the vat.

Inside the vat there is a conveyor belt 19 provided with through holesin the embodiment shown. The conveyor belt is introduced at the bottomend of the vat and extending along the bottom 17 of the vat by means ofcontrol means (not shown), said bottom forming the support for theconveyor belt 19. At the top end 20 the belt 19 leaves the vat 7, passesaround a driving pulley 21 and returns to the bottom end of the vat 7via driving pulleys 22 and 23.

The bottom 17 of the vat 7 is provided with indentations or grooves 24directly adjacent the bottom end wall 11 of the vat 7, said indentationsor grooves being connected with one or more outlets 25 adjacent the endwall 11. Inside the vat there is a diagrammaticly shown scraper plate 26perpendicular to the bottom of the vat, said plate being installed at adesired distance from the conveyor belt 19.

Next to the scraper plate 26, seen in the direction towards the top end20 of the vat 7, there is a prepressing means 27, comprising an endlessbelt 28 provided with weights 29 (shown diagrammaticly) for prepressinga cheese body 30. During operation of the assembly the cheese body isconveyed towards the top end 20 of the vat 7 after having passed the gapbetween the scraper plate 26 and the conveyor belt 19. The prepressingmeans 27 is driven by a driving pulley 31 and is provided with means(not shown) to adjust the distance between itself and the conveyor belt19.

Between the prepressing means 27 and the scraper plate 26 is an inlet 32to a suctions means 33 sucking out liquid from the vat 7. In front ofthe scraper plate 26, seen in the direction towards the bottom end wall11, two rows of teeth 34 and 35 are mounted extending, each like teethon a rake, perpendicular down towards the bottom 17 of the vat to adesired level. The teeth of each rake 34, 35 are mounted adjacent eachother in a direction transverse to the longitudinal direction of the vat7. The height of the teeth is adjustable by means of an adjustment means36 also acting as a means for subjecting the teeth to a reciprocatingmovement in the transverse direction of the vat 7. The outer teeth ineach row of teeth 34, 35 are flexibly journaled to prevent cheese grainsfrom being pressed up along the side walls 18 of the vat 7. Adjacent thetop end of the vat 7 there is provided a cutting means 37 cutting offsuitably dimensioned blocks from the cheese body 30 both in longitudinaland transverse direction. The blocks 38 are conveyed to a secondconveyor means 39 for further, well-known processing.

During operation of the assembly the curd is fed into the vat 7 via theinlet pipe and the chute 12, said curd being automatically distributedacross the entire width of the vat 7 due to the gradual increase inlength of the inlet pipe 9 and the chute 12 in a direction transverse tothe vat. The vat has been provided with a whey pool 39, the surface 40of said whey pool being substantially maintained at its predeterminedlevel during the entire operation. The inclination of the surface 40 andthe vat 7 is adapted such that part of the bottom 17 adjacent to the topend 20 of the vat as well as the prepressing means are above the wheysurface 40, and the mouth of the chute 12 is a short distance below saidsurface 40. The curd thus flows directly into the whey pool 39. Due tothe holes and openings 16 in the bottom 13 of the chute 12 the conveyedwhey flows directly downwards in a direction indicated by the arrow 41towards the bottom end wall 11 of the vat 7, while the cheese grains,shown as dots by the reference numeral 42, fall slowly like snow flakestowards the conveyor belt 19. There they are deposited and form anoblique or almost S-shaped slope 43 inclining towards the bottom endwall 11 of the vat 7. The deposited cheese grains are collected in acheese body 30 moving upwards owing to the movement of the conveyor belt19, towards the reciprocating teeth 34 and 35 providing the cheese bodywith a substantially uniform thickness across the entire width of thevat 7. Subsequent to having passed the teeth 34 and 35 the cheese bodypasses the scraper plate 26 subjecting the cheese body 30 to a slightextrusion and giving it the desired thickness. Thereupon the prepressingis started by means of prepressing means 27, the prepressing processhaving been initiated while the cheese body was still immersed in thewhey pool 39. During the movement of the cheese body 30 upwards towardsthe top end 20 of the vat 7 the prepressing is continued while thecheese body gradually emerges from the whey pool 39. During the lastpart of the movement of the cheese body 30 in the vat before it isconveyed to the cutting means 37 the remaining free-flowing whey drippsoff. During the starting of the assembly until the desired slope 43 hasbeen built up a hight-adjustable block (not shown) can be installed inthe gap between the scraper plate 26 and the conveyor belt 19. When thedesired slope inclination has been reached the conveyor belt is startedand the prepressing initiated, while said block is conveyed up andremoved at the cutting means 37.

The vat can be made of transparent walls for visual monitoring of theoperation of the assembly. The inventive assembly may be provided withdetectors, such as a photocell 44 along the backside of the chute 12,for monitoring the correct built-up of the slope 43. Other photocells(not shown) can be mounted at other locations in the vat for monitoringcorrect operation and desired thickness of the cheese body. Suchphotocells or detectors cooperate to adjust the outlet velocity of thepump 6 as well as the velocity of the whey when flowing out of the vat,such as via the outlet 25 of the suction means 33. The indentations 24in the bottom 17 of the vat 7 constitute a further safeguard for thewhey having the desired direction of flow without unnecessarily whirlingup the cheese grains in the whey pool 39. The whey flows down to theoutlet 25 via the indentations 24 and thus out of the vat 7.

Instead of the prepressing means comprising an endless belt, manually ormechanically installed pressing plates can be used, which are alsomanually or mechanically removed before they reach the cutting means 37.

The inclination of the vat furthermore ensures that a whey pool 39 canbe maintained, and that possible air bubbles are easyly freed from theconveyor belt without meandering into the cheese body.

Instead of the conveyor belt passing down into the vat along the insideof bottom end wall 11 of the vat, cf. FIG. 1, the conveyor belt can bedirectly introduced in the bottom 17 of the vat by means of a gap in theend wall, said gap simultaneously acting as an outlet for the whey,optionally instead of the outlet 25.

The invention is described in its preferred embodiment. Many alterationsmay be made without thus deviating from the scope of the invention.

We claim:
 1. A method for preparing prepressed cheese curd blocks whichcomprises:feeding a curd which comprises a mixture of curd grains andwhey to a conveyor belt below the surface of a whey pool containedwithin an oblong, obliquely arranged vat; and conveying said curd onsaid conveyor belt along an oblique path to a position above saidsurface of said whey pool while simultaneously during said conveying,collecting curd grains, shaping said collected curd grains byprepressing means and side-limiting walls so as to produce a resultingcheese body, and cutting said resulting cheese body into blocks.
 2. Amethod as claimed in claim 1, wherein said curd is fed to said conveyorbelt at a velocity sufficiently slow so that the curd grains aredeposited below said surface of said whey pool with no further influenceon their movement other than the force of gravity and the movement ofsaid whey.
 3. A method as claimed in claim 1, wherein said cheese bodyis conveyed on said conveyor belt below a thickness-regulating scraperplate.
 4. An apparatus for preparing prepressed cheese curd blocks whichcomprises:an oblong, oblique vat defined by a bottom, side-limitingwalls, an open top, and a bottom end wall provided with means forintroducing a conveyor belt into said vat; a support plate extendingalong said bottom of said vat; an endless conveyor belt positionedwithin said vat; a pump for feeding curd comprising a mixture of curdgrains and whey into said vat to said endless conveyor belt via an inletpipe, said endless conveyor belt running along said support plate andextending from a delivery mouth of said inlet pipe to a cutting stationfor cutting off cheese blocks of a predetermined size from a cheese bodyconveyed on said endless conveyor; prepressing means positioned withinsaid vat to press curd grains collected and conveyed on said endlessconveyor belt; and means to maintain the level of the curd fed into saidvat so that said delivery mouth of said inlet pipe is maintained belowthe surface of the curd.
 5. An apparatus as claimed in claim 4, whereinsaid endless conveyor is provided with evenly distributed holes and thebottom of the vat has indentations at least within an area below saiddelivery mouth of said inlet pipe, said indentations being in fluidcommunication with one or more outlet openings positioned adjacent saidbottom end wall.
 6. An apparatus as claimed in claim 4, wherein saidprepressing means extends at least from a position below the surface ofthe curd to a position above the surface of the curd.
 7. An apparatus asclaimed in claim 6, further including a scraper plate for adjusting thedesired thickness of the cheese body positioned in front of saidprepressing means.
 8. An apparatus as claimed in claim 4, wherein saidinlet pipe extends upwardly and over a top edge of said bottom end walland obliquely down into said vat in a direction away from said bottomend wall, said inlet pipe being substantially rectangular incross-section and increasing in cross-section towards said deliverymouth until said inlet pipe has approximately the same width as saidvat.
 9. An apparatus as claimed in claim 8, wherein said delivery mouthof said inlet pipe comprises a substantially planar chute extendingdownward into said vat, said chute being provided with perforations. 10.An apparatus as claimed in claim 4 further comprising horizontallydisplaceable rake means located in front of said scraper plate forleveling the surface of the cheese body before it passes beneath saidscraper, said rake means including outer, flexibility journaled teeth.11. An apparatus as claimed in claim 4 further comprising a suctionmeans located between said prepressing means and said scraper plate forsucking whey from said vat.